Changes in the amount and location of river and meltwater discharge to the North Atlantic and Arctic Oceans could profoundly affect the thermohaline circulation and thus the climate of Europe.

During the last 21,000 years abrupt changes have been recorded in ocean circulation and in the location of the North Atlantic Deep Water (NADW). Palaeodata and modelling suggest these changes may have been caused by ice sheet dynamics (such as changing meltwater inputs and the blocking/unblocking of river channels) and by changes in continental runoff and river discharge caused by climate change.

Through ORMEN there is a concerted effort to understand past changes in NADW formation and to explore the risk of comparable changes taking place in the future. Two coupled ocean-atmosphere-vegetation models will be used to explore the impacts of a range of possible scenarios representing different intervals during the last deglaciation, the choice of which will be informed by new reconstructions of Eurasian ice-sheet deglaciation history. The plausibility of the simulations will be evaluated against a 4D reconstruction of the ocean during the last deglaciation and palaeo-environmental records, before the models are used to examine the consequences of potential future changes in freshwater fluxes on ocean circulation and climate.

We have taken our project acronym from an old Scandinavian legend about an ormen or serpent.

Midgarsormen (Jörmungandr in Old Norse) was the second eldest child between Loki the Trickster and the giantess Angrboda. Kidnapped by the gods, he was cast into the waters that surround Midgard (the Middle Earth - realm of the humans). There he laid until he grew so large that he was able to wrap himself around Midgard, (hence Midgard Serpent). He continually gnaws at the roots of Yggdrasil, the World-Tree, causing a creeping rot that will topple the Tree at Ragnarok, and meanwhile being the source of earthquakes, and the tides are following his breath. Ragnarok was the doom of the gods and men, and heralded the destruction of the Nine Worlds. Nothing will escape the coming destruction, whether you live in heaven and on earth.